Erythropoietin, a glycoprotein hormone, is recognized as the primary hormonal material exercising control over red blood cell production. This laboratory routinely uses a quantitative radioimmunoassay specific for human erythropoietin that measures both fully sialylated and asialoerythropoietin, and also uses the biological assay in the plethoric mouse to measure fully sialylated erythropoietin activity. We propose to combine this capability and that acquired from extensive investigations involving the isolation and complete characterization of protein and glycoprotein substances similar to erythropoietin. We propose to isolate and characterize human erythropoietin from crude urinary extracts. Specific objectives are to: 1) re-examine methods used for the isolation of this and other like substances; 2) examine other methods involving: a) affinity chromatography with plant and animal lectins; b) biaffinity chromatography with 1) purified erythropoietin; 2) anti-erythropoietin antibody; 3) combine the most useful methods and employ them to isolate highly potent, purified erythropoietin in quantities commensurate with the original supply of crude extract for use by us and for distribution to others; 4) use highly purified erythropoietin to a) prepare a highly specific anti-erythropoietin antibody from rabbit serum b) determine the chemical and physical properties of erythropoietin c) re-examine with pure erythropoietin biological parameters determined in the past with very impure hormone and d) extend ongoing studies in animal models and tissue preparations concerned with the biogenesis and mechanism of action of erythropoietin.